1. Field of the Invention
This invention is generally directed to supports or harnesses for retaining electrical wires or cables in orderly relationship and, more specifically, to wiring harnesses for use with conventional internal combustion engines for supporting spark plug wires extending between an engine's distributor and the spark plugs. The wiring harnesses of the invention are structured so as to positively and orderly maintain the spark plug wires in spaced relationship with respect to the engine block and each other to thereby reduce the damaging effect to the wiring insulation due to heat dissipated from the engine and to prevent electrical arcing or shorting between adjacent spark plug wires. The wiring harnesses of the present invention may also be secured to engines utilizing existing bolts so that no modifications are required to engine blocks or other components.
2. History of the Related Art
The use of harnesses for organizing electrical wiring is well known in many industries. In most instances, such wiring harnesses are utilized to securely maintain wires within a fixed bundle so that the wires are not accidently displaced or accidently damaged, thereby interrupting an electrical circuit. However, harnesses also are utilized to facilitate identification of electrical wires by retaining the wires in an orderly relationship with respect to one another along any given electrical system.
In the automotive industry, wiring harnesses have been utilized to organize and support the electrical spark plug wires which extend from an engine's distributor to the spark plugs associated with the combustion chambers of the engine. In U.S. Pat. No. 2,997,531 to Oldham et al., an insulating support for the spark plug ignition wires is disclosed which incorporates a bracket which is mounted to the valve cover and to which a clip is selectively attached. The clip member includes a plurality of slots in which the spark plug wires ma be selectively frictionally received. The supports were designed to reduce the capacitance between the spark plug wires and the engine components to a minimum. Unfortunately, such a mounting arrangement requires that modifications be made to the valve cover by way of separate mounting attachments to secure the brackets of the insulated supports to engine valve covers. Further, the supports are not designed to provide efficient spacing between the spark plugs and the hot spots of an internal combustion engine and thus do not effectively reduce potential damage to the insulated coverings of the spark plug wires. After numerous hours of engine operation, spark plug wires will begin to deteriorate causing cracks in the insulated walls or coverings of the wiring resulting in the potential for electrical arcing between the conductors of the spark plug wires and adjacent metallic components or adjacent electrical wires. A further problem associated with such wire supports is that the spark plug wires are only frictionally retained by the brackets and therefore can be easily displaced during routine engine maintenance or by vibrations caused by normal engine operation.
In U.S. Pat. No. 3,342,168 to Burdette, another spark plug wire harness system is disclosed which was specifically designed to decrease inductive losses through the spark plug wires by way of arcing between the conductors of one wire relative to another or from the conductors of a wire relative to the engine. The system utilizes spark plug wires of essentially the same length which are mounted by both fixed brackets which are secured to various components of the engine, such as the air filter or valve cover, and floating brackets which are utilized to retain the spark plug wires in spaced relationship with respect to one another between the fixed brackets. Although the wiring harness of this patent does provide brackets for mounting the spark plug wires in spaced relationship from the hot spots of the engine, the fixed brackets and the floating brackets are designed to frictionally receive the spark plug wires within slots provided in each member. As with other such harnesses, the electrical wires may be accidently displaced from within slots in which they are frictionally engaged either during routine maintenance or by the result of normal engine vibration, thereby allowing the wires to make contact with hot spots of the engine which can result in deterioration of the insulating covering or jacket of the spark plug wires. Further, the harness system requires that modification be made to existing engine components such as by providing mounting bolts which are utilized to secure the fixed brackets to the air cleaner or to other engine components. Due to the different configurations or paths which spark plug wires must follow in each internal combustion engine, in order to properly install such a harness system, an individual must make modifications to the equipment to properly align each of the brackets before the brackets ar secured to the engine components.
An additional example of a spark plug wire retainer which utilizes grooved supports for the electrical wiring is disclosed in U.S. Pat. No. 4,771,743 to McDowell. As with the harness systems discussed above, such a system does not provide for a secure retention of the spark plug wires, especially in an environment where the wires are subjected to constant engine vibration which can work to dislodge the spark plug cables from the supporting brackets.
Other prior art examples of wiring harnesses are disclosed in U.S. Pat. No. 2,343,314 to Miller et al., U.S. Pat. No. 3,920,887 to Kloos et al., and U.S. Pat. No. 4,366,939 to McMillan.